There is no “execution” semantics in Capella DFD, and by the way no “Activity start” and “Activity end” … So you cannot interrupt something which has not started! 
It is somehow different from UML2/SysML activity diagrams, as explained in the Capella web page.
To sum up: Capella IS NOT a SysML tool, even if you can mimic a lot of SysML diagrams with it…